i have one, but have not used it much. What sensors do you want to use with it? Each I2C sensor will need a separate address. It should be possible to change addresses from the defaults with leJOS but we have not added methods to make this easy.

I just got one in the mail a few days ago but haven't played with it much yet. As Lawrie mentioned, I think you need to set each sensor with a unique address on the I2C bus. I'll look into this shortly.

Thanks guys I think by looking at the mindsensors site the only Lego sensor supported in the ultrasonic sensor but I have a compass sensor and irSeeker that should work with it to as I think there digital. Thanks again for looking at this for me.

Mindsensors sensors let you change the address by sending the command
0xA0, 0xAA, 0xA5, <new I2C address>
to the sensor. This can be done the sendData method of I2Sensor or any sensor class that inherits from this. The new address can then be specified by calling setAddress on any I2C sensor class. (The address used on setAddress is <new I2C address> divided by 2).

Are you using the Mindsensors or the HiTechnic compass sensor? I am not sure if you can use the same command to change the address with HiTechnic sensors and the Lego ultrasonic sensor.

I have a mindsensors and hi-technic compass sensor. All the logo sensors and an irSeeker also made by hi-technic. I don’t need to do this urgently I was just interested if lejos supported using the port splitter and how you would do this.